Granulocyte colony stimulating factors (G-CSFs) stimulate the proliferation and differentiation of myeloid progenitor cells, improve cell survival and affect some end-cell functions, through binding to G-CSF receptors present on all cells of the neutrophilic granulocyte lineage. Filgrastim (recombinant G-CSF) is frequently used among patients with cancer including those with haematological malignancies. In-vivo studies and studies in healthy people show that SC administration of CSF results in lower peak but more prolonged and stable levels of G-CSF as compared with Intravenous (IV) administration, with similar or higher neutrophil counts. It is safe to assume that IV administration of G-CSFs would be more comfortable to patients when hospitalized, especially during or after chemotherapy when most patients have a central catheter and are thrombocytopenic. However, it is necessary to ensure that the same effects are obtained with both methods of administration.